Automatic toaster



Feb. 3, 1942. A. sTRAusS- AUTOMATIC ToAsTER Filed Dec.' 1s, 1939 J1- f 16 'f MM W Feb. 3, 1942l f A. STR/wss 2,271,520

AUTOMATIC TOASTER v Filed Dec. 13, 1939 Sheets-Sheet 5 HL Fifa .s naves,

Patented Feb. 3, .19472, l

AUTOMATIC roAs'rEa Alfred Strauss, Chicago, Ill., assigner, by mesne i assignments, toMcGraw Electric Company, a

corporation of Delaware Application December 13, 1939,- Serial No. 309,084

` claims. (c1. 21a-1 9) This invention relatesin general'to automatic toasters, and'more specifically to novel mechv anism operable in conjunction therewith for au-` tomatically timing a toasting operation-and ejecting the toast from the heating zone at the termination of such an operation.

A. principal object ofthe invention is the provision of novel timing'mechanis'm in an automatic toasterrwhich is extremely simplified in construction and positive and accurate in operation. v

Another important object of the invention is the provision oi means for automatically' timing v.ui

a cooking operation 'which employs an. electrically heated thermostatic element which itself automatically terminates the heating thereof,f

and which, in the subsequent cooling thereof,

causes the product being cooked to be ejected' from the heating zone.

A further important object of the invention the provision in such ya timing mechanismfof novel means for manually varying the initial tension in the thermostatic strip employed.

Another object of the invention is the provision of an auxiliary thermostatic element in such a timing mechanism which functions 'to automatically vary the initial tension,.on":the,v

main thermostatic strip in accordance 4'withfthe temperature of the cooking apparatus.

Numerous other objects and advantages of the invention will be apparent from the following:

description, which, when taken in connection with the accompanying drawings, discloses apreferred embodiment thereof. v

In the drawings, v Figure 1 is a longitudinal'section of an automatic toaster embodying the features oi the in- Referring more particularly `to the drawings, reference numeral II indicates in general the housing of an automatic toaster which may be Aof any desired shape andconstructiom and pref-l erably includes a three-sided shield Vor inner housing I2 disposed therein with its open side at the right of Fig. 1. The housing ismounted upon a suitable hollow base of molded composition material, such as Bakelite, indicated byreference numeral I0, within which the timing mechanism to .be later described is disposed. The

various parts of the timing mechanism are mounted on a plate |3.lwhich is secured inside the hollow base I0 by means of screws. Thehousing 4|| is open at its top and right hand side (viewing Fig. 41), and asuitable closure member and Vbread carrier, indicated generally by reference numeral I4, is pivotally mountedA on the plate I3 at l5, and is adapted to be `manually swung to its closed position of Fig. l by means of a suitable vhandle I6. A crumb tray |'I is slid- '.ably disposed within the housing f| |v below the bread carrier Il on the upper portionfcf the base I0, and is adapted to be removed through a suitable aperture ln the left side of the casing II f viewing Fig. 1.

The bread carrier Il is preferably provided with two slice holding elements I8 which arey arrangedin spacedv parallel relationship to each stant invention taken'onl the line |-I` of Figi ure 3;

Figure 2 is a view similarto Figure 1 with the parts shown in vtheir positions' at the completion of a toasting operation;

Figure 3 is a horizontal sectional view taken substantially on the line 3-3 of Figure 1;

Figure 4 is av view similar to Figure 3 with the parts shown in an intermediate position during a;

toasting operation;

Figure 5 is a 'horizontalsectional view taken substantially on the line 5-5 of Figure 2;

Figures 6 and 7 are vertical detailed sectionall viewsl taken substantially on the lines 6-6 and |--'I, respectively, of vFigure 3 and Figure 8 is a diagrammatic view or wiring diagram of the circuits employed in the instant device.

other.` A plurality of heating elements I 9, shown `herein as three in number, are disposed in the usual manner within the housing I| interiorly of the inner shield I2 on either side of and between the slice holding elements I8. It will be readily apparent from Fig. 1, u thatwthe crumb tray Il functions Vto aidin insulating the-mechanism disposed therebelow, which will be later described, from the heating effect of the coils |9.

As shown in Fig. 8, the several -heating elements I9, which'- may be of any suitable constructiom' are connected in series with an auxiliary heatingvelementu and a pair of binding posts or terminal pins 2| 'Thefpins 2|' are adapted lto be connected in the usual manner to a suitable .source of 'electrical' current. Contact members 23 are connected by leads 25 withjends oi auxiliary heatingr element 24.` The contact members 23'and posts 2| are mounted upon the plate I3 andare electrically insulated therefrom in any suitable manner. A movable contact or switch member, indicated generally by referencefnumeral 26, yis mounted upon the platev |3 in a manner to be laterdescribed, and is adaptedv when in closed position of Figs. 4 and 5 to contact the two stationary members 23 to shunt out the auxiliary resistance 24.

That portion of the bread carrier I4 which supports the same and is pivoted to vertical wing extensions 28 of the plate |3 at I5 constitutes a bracket member 21 of substantially L-shape. lIteferring more speciiically to Figs. 1. 2 and 6, a substantially vertically disposed pawl 28v of bar shape, is pivotally mounted adjacent. its upper end at 23 upon the bracket 21 and is urged in a clockwise direction by a suitable spring 3|. On its right hand edge. viewing Fig. 6,-the pawl 28 is provided with a lateral extension 32 which is adapted to contact a vertical edge of the bracket 21 to limit pivotal movement of the pawl in a clockwise direction.

An actuating member 33 is pivotally mounted at 34 on the plate I3. A spring 35 is connected at one end to the plate I3 and at its other end to actuating member 33 adjacent the righi hand end thereof, viewing Figs. 1 and 3, which tends to urge the right hand end of the actuating member 33 upwardly. This right hand end oi the actuating member 33 is provided with aroller 36 which is positioned in the path of movement oi the lower end of the pawl 28 as the latter is swung with the bread holder I4 in its movements between operative and inoperative positions. When the bread holder I4 has been swung in a counter-clockwise direction to almost its closed or operative position, the lower end of the pawl 26 abuts against the roller 36 to move the actu- 1 ating member 33 in clockwise direction, viewing Fig. 1, against the action of the spring 35. Further swinging movement of the bread holder I4 to a small extent forces turning movement in a counter-clockwise direction of the pawl 28 because of the extension 32 thereon engaging an edge of the bracket 21, so that the lower lefthand edge of pawl 28 is on the right of and in contact with the roller 36.

A yoke or latch member 31, which is substantially U-shaped, is pivotally mounted at its upper end ,at 38 on the plate I3, andls provided with a substantially horizontally disposed shelf or cross portion 38 which is adapted to engage beneath the left hand end of the actuation member'33, as 'shown in the drawings, to maintain the latter in its operative position of Figs. 1, 3 and 4. A link or trip member 4I is pivotally connected intermediate its ends by means of a pin 42 to the yoke or latch member 31. The right hand end of the trip member 4I, viewing Fig. 1, is connected toone end of a coil spring 43 which in turn is connected at its other end in any'suitable manner to the plate I3. The spring 43 urges the yoke or latch member 31 to the right or in a counterclockwise direction to maintain the same in latching-aosition of Fig l. A lateral projection 44 is provided on the upper side of the actuating member 33 at the left-hand side of its its pivot point 42 and the point of connection of the spring 43 therewith when the actuating member 33 is turned in a counterclockwise direction by its spring 35. In such downward movement of the actuation member 33, the projection 44 turns the trip member 4| a short distance in a clockwise direction.

The other or left hand end of the ltrip member 4| is provided with a cutaway portion or recess 45 in its lower surface to provide a nose or shoulder portion 46 adjacent the. end thereof. This left hand end of the trip member 4| extends through a suitable aperture in a lai-metallic strip or thermostatic element 41 which is rigidly connected at its opposite end at 46l to one end of a casing or housing 49 which is in turn mounted in any suitable manner upon the plate I3. The casing 43 is open on the side next to the thermostatic element 41 and houses the auxiliary heating element or resistance 24 above referred to.

The free end of the thermostatic element or bi-metallic strip 41, which is that end adjacent the trip member 4I, is engaged by the bifurcated end of a link 5I (Figs. 3, 4 and 5). The other end of the link 5I is pivotally connected at 52 to a lever 53 adjacent the free end thereof. The opposite end of the lever 53 is pivotally mounted upon the plate I3 at 5I), Intermediate its ends, the lever 53 is provided with an aperture 55 through which the lower end of secondary bimetallic or thermostatic strip 56 extends. The upper end of the secondary thermostatic element 56 is rigidly connected at 51 (Fig. 2) to the inner g casing I2 disposed within the outer housing II of the toaster. The free end of the lever 53 is connected to one end of a coil spring 54, the

other end of which is connected to one end of a.

bell crank 58 (Fig. 1). i

The bell crank 58V is pivotally mounted at 59 intermediate its ends upon a laterally movable slide 6I, the upper surface of which engages the lower surface of a shelf portion 62 (Figs. 1, 3

. and '1 formed on the left end wall ofthe molded base I8. The other end oi the bell crank 58 is engaged by the upper end of a screw 63 extending through a suitable tapped bracket 64 mounted upon the slide 6I. The screw 63 is adapted to adjust the bell crank 58 to initially tension the spring 54 to the degree desired.

pivot 34, which projection is adapted to contact the upper edge of the trip member 4I between? A stud shaft 65 is mounted for rotation in one end wall of the base III (Fig, 1) and extends through a suitable slot 66 in the slide member 6|, as shown in broken lines in Fig. '1, to guide the longitudinal movements of slide 6I. A cam member 61 is rigidly secured to the inner end` of the shaft 65 and is adapted to engage a lug v or offset portion 68 on the slide member 6I. The outer end oi' the shaft 65 is provided with a suitable han'dle 69. Rotation of the handle 68 moves the cam member 61 to adjustably position the slide 6|, so that the desired tension vmay be manually set in the spring 54 for a purpose to be later described.

A bell crank 1 I, comprising part of an auxiliary latching mechanism, is pivotally mounted intermediate its ends at 12 to the plate I3. The longer of the arms of the bell crank 1I engages a pin 13 or other suitable means mounted on the link 5|. The other end of the bell crank 1| is adapted to cooperate as a latch withl one end of a lever 14 forming a part of the switch 26 above referred to. The lever 14 is pivotally connected intermediate its ends on a stud 15 which is mounted upon the plate I3. The other end of the lever 14 is engaged by oneend of a spring 16 which is mounted upon the stud 15 'and the other end of which engages a suitable stud` 11 mounted upon the longer arm of the bell crank 1I. 'I'he spring 16 thus urges the bell crank 1| in a counterclockwise direction, viewing Fig. 3, and the lever 14 in a clockwise direction about their respective pivot points 12 and 15. A contact member 19 is pivotally connected to the lever 14 intermediate its pivot point 15 and the end thereof which cooperates with the bell crank or latch member 1 I. A lever or arm 6| is connected to the actuating member 33 (Figs. 3, 4 and 5) which is adapted to contactthe other end of the lever 14 to swing the latter in a counterclockwise direction when the actuating member 33 is swung in a clockwise direction (viewing Fig. 1) as it is moved to operative position. Such movement 6 of the lever 14 results in the swinging of the free end thereof out of the path of movement of the end of the bell crank or latch 1I from its positions of Figs. 4 and 5 to its position of Fig. 3. This movement of the lever 14 permits the spring` l0 16 to move the bell crank '1I into its latching position of Fig. 3 wherein it retainsthe switch member 26 in open position, as shown in' 3. The bread carrier or slice holder I4 is 'provided with a downwardly extending arm 82y which is"l-5 adapted to cooperate with a curved leaf spring 33, connected at one end in any suitable manner to the plate I3, when the bread holder I4 is moved to the inoperative position (as shown in Fig. 2) to cushion such movement. 20

The operation of the above described device is as follows:

When it is desired to perform a toasting operation, the bread to be toasted is inserted in the slice holder I4 and the latter is moved from its 25 inoperative position of Fig. 2 toits operative position of Fig. 1. In such movement of the slice holder I4, the pawl 28 impinges against the roller 33 and moves the actuating member 33 from its inoperative position of Fig. 2 to a point slightly 30 beyond its operative position of Fig. 1, whereupon the end of pawl 28 slips oi the roller 36 and member 33 is released. In such movement of the actuating member 33, the yoke or latch member 31 is first swung thereby in a clockwise direction 35 and is then returned by the spring 43 to engage beneath the free end of the actuating member 33 when the latter is released by pawl 28. At the same time, the lever 8| on the actuating member 33 moves the switch member 26 from its 40 closed position of Figs. 4 and 5 toits open position of Fig. 3 where it is maintained by the latch member 1I, as above described. As soon as'the binding posts 2I have been connected in the usualk manner to a source of electrical energy, the heat- 4.5 ing elements I3 are energized. Since the switch 28 has been moved to open position, as above explained, the heating element 24 is also energized, the latter being connected in series with the heating elements I9, as shown in Fig. 8. 50

The auxiliary heating element or resistance 24 heats the thermostatic element or bi-metallic strip 41 to cause the latter to be deformed and moved from its normal position of Fig. 3 to its expanded or iiexed position of Fig. 4. This move- 55 ment of the thermostatic element 41 rotates the member 5I on its pivot 52 andisjopposed by the resistance of the spring 54 as applied to the strip by means of the membersv 53 and 5I, until the member 5I passes dead center, whereupon the 60 strip suddenly moves to the position shown in Fig.

4. This expanding movement of the thermostatic element 41 moves the bell crank or latch 1I from its latching position of Fig. 3 toward its inoperative position of Fig. 4, and near the end of the g5 movement of the thermostatic element 41, the latch 1I frees the lever 14 and permits the contact member 19 to bridge the stationary contacts 23. Such movement of the switch member 26 to rclosed position is accomplished by the spring 13, 7o

and is not interfered with by the member 8 I, since the latter has been moved past the lever 14 in the above described movement of the actuating member 33 to operative position.

Closing of the switch member 23 shunts out the 75 auxiliary resistance'or heatingv element to deenergize the same and permit the thermostatic'element or bi-metallic strip 41 to cool'and return' to its normal positionof'Figs. 5y and 3. As'the elementy 41 returns toward its position of Fig. 5, its movement is opposed by spring 54 as before,I andthe movement is delayed until the element has cooledvsuillciently to rotate member 5I past dead center, whereupon the return to norxrial position is suddenly completed. Near the end of its return ,movement element 41 engages 'the shoulder or nose 4Iiv of the trip lever 4I'to pull the latter to the left against the'tension of the spring 43. This movement of the trip lever 4I swings the yoke or latchv member 31` in a clockwise direction (viewing Figs. v1 and 2)v to release the actuating member 33. When thus released, the actuating` member 33 is swung in a clockwise direction b the spring 35 and the roller 36 abuts against the b ket member 21 to' move or kick the slice holder from its operative position of Fig. 1`to its inoperative position of Fig. 2. Such movement of the sliceliolder I4"'is cushioned by the spring 33, as above described. Ihe` downward movement ofthe previollsly latched end of the actuating member 33 resultspin the lip 44 y thereon impinging against the leverJ'I to disengage the free end of the latter from`\the lower surface of the associated aperture in th-bime tallic element 41. The parts thus assume their several normal positions, so that they may again be readily returned to operative position merely by the movement oi'- the slice holder from inoperative to operative position.

From the above description it will be seen that the duration of the timing operation is determined by a heating and a subsequent cooling of the thermostatic element 41. This predetermined period of time maybe varied manually by actuation oi the control handle 83 tol move the cam 31 to vary the initial tension in the spring 34. The tension maintained In the spring 54 is directlytransmitted to the thermostatic element 41 by the members 53 and 3|.' That'is, the

` movement of element 41 on heating or cooling ro.- y

tates member 5I on its pivot, thereby rotating lever 53 on its pivot against the tension of spring 54. The screw 63 is employed for the'purpose of setting a desired initial tension in the spring 54 when the device is originally tested in the factory. The tension may also be varied as stated above by means of the adjusting handle 69, and thus the toasting period may be varied manually by the user to produce light or dark toast, as desired.

In addition to theabove described manual variations or alterations of the toasting period, it has been found desirable to provide automatic means for varying this period in accordance with the-temperature of the toasting device. This'is necessary for the obvious reason' that over a period of continued use, the lroasting apparatus assumes a higher initial temperature than is the case when it is first put into operation. This dliference in the temperature of the apparatus, and its resulting, effect upon the cooking operation, is automatically compensated for by the auxiliary thermostatic element or bi-metallic `strip 56. The element 36 is tensioned so as to tend. to rotate lever 53 vin the same direction as ring 54, and its effect is thus added to that of pressure being substantially entirely relieved by the time the toasting apparatus reaches its maximum temperature. In this manner, an increase in temperature of the toasting apparatus automatically results in a speeding up of the toasting operation, with the result that the toast is always turned out in the desired condition.

It is thought that the invention and its attendant advantages will be understood from the foregoing description, and it will be apparent that various changes may be made in the form, construction and arrangement of the parts without departing from the spirit and scope of the invention or-sacriiicing any of its material advantages, the form hereinbefore described being merely a preferred embodiment thereof.

I claim:

1. In a bread toaster, a toasting compartment,

a toggle device of which one arm is a bi-metallic strip and the other arm is a pivoted member, a lever on which said member is pivoted, an adjustable spring acting on said lever in the proper direction to collapse said toggle device, means for operating said device by heating and cooling said strip, means for terminating a toasting operation by operation of said device responsive to cooling ofl said strip, anda second bi-metallic strip receiving heat from said compartment, said last mentioned strip interfitting with and initially pressing said lever in the same direction asl said spring and being adapted to apply a decreasing force to the lever as the temperature of the toasting compartment increases.k

2. An automatic electric toasterA comprising toast heating elements, a bread carrier normally yieldingly biased out of direct heat receiving relation to the toast heating elements and movable into direct heat receiving relation relatively thereto, a pivoted latch for holding the bread carrier in `said direct heat receiving position, a trip bar connected with said latch and having a recess in` one edge and a thermal timing means for causing release movement of said latch to terminate a toasting operation, said timing means including a bimetal bar fixed at one end, a toggle arm engaging the free end of the bimetal bar, a lever arm vpivotally supporting the toggle arm. manually adjustable spring means to bias the lever arm to effect initial longitudinal compression of the bimetal bar and cause it to move with a snap action, means to heat and then to cool the bimetal bar to cause it to move in one direction and then .in the return direction, spring means to press said one edge of the trip bar against the bimetal bar, said bimetal bar moving into the vrecess in the trip b ar during heating v thereof and causing movement of the trip bar and release of the latch on cooling whereby termination of a toasting operation is effected.

3. A device as set forth in claim 2 and including a second bimetal bar subject to toaster temperature having interiitting engagement with said lever armv and effective to cause a decrease in the compression of the bimetal bar With increase in toaster temperature to ensure substantially vuniform toasting of successive slices of bread with varying toaster temperature.

4. An automatic electric toaster comprising a toasting chamber containing'heating elements, a bread carrier movable into toasting and nontoasting position relative to `the heating elements and ybiased to non-toasting position, thermal timing means for terminating a toasting operation comprising'a 4bi-metallic strip fixed at one end, a pivotally mounted lever arm, a toggle arm pivotally mounted on said lever arm and having a free end engaging the free end of the bimetallic strip, spring means acting on the pivoted lever arm to bias the toggle arm and the bi-metalllc strip so as to cause the bi-metallic strip to move with a snap action, means to heat andthen to cool the bi-metallic strip to cause it to move in one direction and then in the return direction, and means for holding 'the bread carrier in toasting position releasable in response to the snap movement of the bi-metallic strip upon cooling.

5. An automatic electric toaster as set forth in claim 4 including a second bi-metallic strip subject to toaster temperature engageable with the pivoted lever arm and eiective to cause a decrease in the bias on the toggle arm and bi-metallic strip with increase in toaster temperature to insure uniform toasting of ysuccessive slices 0f bread withvvarying toaster temperature.

ALFRED STRAUSS. 

